Fuirena squarrosa is most similar to F. pumila in perianth except it is perennial; to F. breviseta except its distal sheaths are hirsute, not glabrous; and to F. bushii except its perianth blade is flatter and the anthers shorter.

Plants of the Gulf and Atlantic coastal plains and inland to adjacent provinces east of the Mississippi River usually have closely set cormose rhizome buds.